The use of doped semiconductors to create barriers, injectors, tunnel junction contacts, cascade LED junction, and other related device has long been known in the art. Specially, conventional semiconductor materials can be comprised of doped semiconductor layers placed into contact with each other to create one or more p-n junctions. In the case of light emitting diodes (LEDs), as electrical current is applied to the junctions, electrons and holes combine with each and emit photons. The energy contained in the emitted photos corresponds to the energy difference between the respective holes and electrons.
Small, lithographically patterned metal contact structures on the semiconductor layers supply the current to be injected into the junction. The electrical resistance of the injecting semiconductor layers, though, can inhibit the uniform spread of current across the junction surface away from the metal contact. Completely covering the surface, instead, with a low-resistance metal contact layer to spread out the current can block light generated in the crystal from being extracted.
Accordingly, there are a number of improvements that can be made within the art.